Crusher



Jan. 2, 1934. H. G. WELSFORD ET AL pnusmm Filed March 17, 1931 INVENTORS H UBEH'I'IGMIELSFORD AN DREWLLRUSSELL yflwfi M/ JLTTOBNEY FIGl Patented Jan. 2, 1934 UNITED STATES CRUSHER Hubert G. Welsford and Andrew N. Russell, Montreal, Quebec, Canada Application March 17, 1931. Serial No. 523,216

2 Claims.

mounted within a vertical shell having a top.

inlet and a bottom outlet,. said shell and plug being spaced apart to provide an intervening annular passage through which the material travels downwardly from the inlet to the outlet. The important novel feature of this construction is the rotation of the plug at such a relatively high speed that the material, during its passage from'the inlet to the outlet, is repeatedly hurled into violent disintegrating impact with the opposing surfaces of the plug and shell. In this respect the present invention differs radically from rotary crushers of the gyratory type in which the crushing action is due to the gy'ratory motion of the crushing head within and relative to the surrounding concave. This invention also differs, in its mode of operation,

from previously known rotary crushers of the non-gyratory type in which the rotor or crushing head is mounted to maintain its concentric relation to the shell during the crushing operation. In all of the latter types of crushers as heretofore designed the crushing of the material is accomplished solely by attrition, whereas, in accordance with this invention, the crushing is due to the momentum with which the material is repeatedly hurled from the plug to the opposing surface of the shell and vice versa.

Another feature of importance is that the relative angles of the opposingwalls of the annular passage defined by the plug and shell are such that the material, during its downward travel, is repeatedly returned to the plug after being hurled therefrom into disintegrating impact with the opposing surface of the shell.

A further feature of the invention resides in a gradual reduction in the cross sectional area of the annular passage towards the lower end of the plug which is preferably predetermined so that the annular clearance at the inlet to the shell bears a certain relation to the diam eter or size of the uncrushed-particles of material supplied to said inlet while the annular clearance at the outlet of the shell bears a certain relation to the maximum size of the crushed particles. Generally speaking, the annular clearance at the inlet is about three times 0 the diameter or size of the uncrushed particles while the diameter at the outlet is from 1 to 2 times the maximum diameter or size of the crushed particles.

A; still further feature of the invention is that 5 it provides for a gradual increase in the surface velocity of the portions of the frusto-conical plug with which the material being crushed is gradually brought into engagement as the size or mass of the particles of the material is reduced. In this way the velocity imparted to the material by the rotating plug is increased as the size or mass of the material is reduced and ensures efiicient crushing of the material during its entire travel between the opposing surfaces of the plug and shell.

A still further feature of the invention is the provision of longitudinally extending grooves or corrugations in the opposing surfaces of the plug and shell, whereby the emciency of the disintegrating action to which the material is subjected during its passage between said surfaces is considerably increased. These longitudinal grooves or corrugations decrease in pitch or fineness from the inlet to the outlet of the shell in order to compensate for the gradual reduction in the size or mass of the material as it progresses towards the outlet.

Proceeding now to a more detailed discussion of the invention, reference will be had to the accompanying drawing, wherein Figure 1 is a vertical longitudinal sectional View through a centrifugal crusher constructed in ac cordance with this invention.

Figure 2 is a transverse sectional view in the plane of the broken line 22 in Figure 1.

Referring more particularly to the drawing, 11 designates a vertical shell. formed with a slight inward taper towards its upper end. The lower end of the shell is mounted upon a base casting 12 to which it is secured by the bolts 13 passing through the flanges 14 and 15.. The lower end of the shell projects somewhat below the flange 1% and is received in a recess 16 formed at the inner edge of the flange 15. The inner surface of the shell is provided with a removable lining consisting of a series of superimposed rings 18, the lowermost one of which is supported upon a shelf 19 formed in the base casting 12. The uppermost ring 18 has a smooth inner surface 18a and is provided at its lower edge with an inwardly projecting annular ledge 20 having a sloping upper surface 21 arranged so that the material falling thereon is deflected towards the centre of the shell and onto the upper end of the rotor or frusto-conical plug generally indicated at 22. The inner surface of each remaining ring 18 is corrugated to provide, in effect a circular series of grooves 23 extending in the longitudinal direction of the shell. Each groove 23 is blocked at its lower end by a ledge 24 having its upper surface 25 sloped so that any material falling thereon is directed inwardly towards the centre of the shell and onto the plug 22. If desired the upper ring 18 may have its inner surface provided with the grooves 23 instead of being made smooth, as previously described.

In the present instance the frusto-conical plug 22 consists of a series of superimposed rings 26 surrounding the stepped portions 27 of a vertically disposed shaft 28. Each ring 26 is made of gradually increasing diameter towards its lower end and is provided with a corrugated outer surface affording a series of longitudinal grooves 29 corresponding generally to the grooves 23 of the opposing shell rings. As shown in the drawing the outer inclined surface of each ring 26 forms a symmetrical continuation of the corresponding surface of the ring next above and thus imparts to the plug the frusto-conical configuration previously referred to. It will also be noted that there is a gradual or stepped reduction in the pitch or fineness of the grooves 23 and 29 as they approach the lower ends of the shell and plug.

The material to be crushed is preferably supplied to a feed hopper 30 at a measured or fixed rate depending upon its hardness. The hopper 30 is suitably supported in the top opening 31 of a feed chamber 32 which is mounted on the upper end of the shell 11 and is secured in place by the bolts 33 passing through the flanges 34 and 35. As the material leaves the hopper30 it is uniformly distributed around the side walls of the feed chamber 32 by means of the conical spreader or distributor 36 which is suitably fixed to the upper end of the shaft 28. The inclined surface 37 of the distributor or spreader is herein shown as being perfectly smooth, but it will be readily understood that this surface may be ribbed or corrugated in any desired manner to facilitate the distribution of the material as it enters the feed chamber 32. The upper half 38 of the feed chamber is shown as sloping downwardly and outwardly from the opening 31 to an intermediate point 39 while the lower half 40 of said chamber is shown as sloping inwardly and downwardly from the point 39 to a bottom opening '41 communicating with the upper end of the annular passage 42 reserved between the plug rings 26 and the shell rings 18. Due to the frusto-conical shape of the plug 22 and the taper of the opposing surface afforded by the shell rings 18 the annular passage 42 gradually decreases in cross sectional area from its upper to its lower end. At its lower end the passage 42 communicates with a chamber 43 which is formed in the base casting 12 and is provided with a sloping bottom wall 44 along which the crushed material received from the passage 42 is conducted to an outlet conduit 45. The sloping wall 44 is formed with an integral bearing 46 having a bushing 47 in which the lower portion of the shaft 28 is mounted, the extreme lower end of said shaft being directly coupled to an operating motor 48 through the medium of any suitable form of flexible coupling generally indicated at 49. The upper end of the shaft 28 is similarly mounted in the bushing 50 of a bearing 51 carried by the spider 52 arranged in the lower portion of the feed chamber 32. The portion of the shaft immediately below the spreader or distributor 36 is threaded to receive an adjusting nut 53 having its lower end supported by a thrust bearing 54 resting on the bushing 50. Packing rings 55, of any suitable form are arranged in the upper and lower ends of the bearings to engage both the adjusting nut and the shaft 28, as shown to advantage in Figure 1. Similar packing rings 56 are also interposed between the lower portion of the shaft 28 and the upper and lower ends of the bearing 46. By turning the adjusting nut 53 the shaft 28 may be raised or lowered in its bearings 46 and 51 to vary the clearance reserved between the opposing surfaces of the plug and shell.

In operation the conical plug 22 is driven at a high rate of speed by the motor 48 and the mounting of the shaft 28 is such as to afford a fixed vertical axis about which the rotor turns in concentric relation to the opposing surface afforded by the shell rings 18. The material to be crushed is fed to the hopper 30 at the fixed or measured rate previously referred to by any suitable means such as the feed beltgenerally indicated at 58. As it falls through the opening 31 the material is uniformly distributed around the feed chamber 32 by means of the spreader or distributor 36. Due to the inclination of the lower portion 40 of the feed chamber the material, as it passes downwardly through the bottom opening 41, is deflected onto the upper end of the conical plug 22 from whence it is immediately hurled at high velocity against the opposing grooved surface 23 of the shell. The resulting violent impact causes the material to be partially disintegrated and to be reflected back onto a lower portion of the plug from whence it is again immediately hurled into violent impact with a lower portion of the opposed shell. This action is repeated throughout the progress of the material downwardly through the passage 42 until the material has become so reduced in mass as to lose all radial momentum. Due to the relative angles of the opposing surfaces of the plug and shell elements it will be evident that partially crushed material tending to fall in a direct downward path afterbeing thrown into impact with the shell will be caught on a lower portion of the plug and again projected into disintegrating impact with a lower portion of the shell. Also, any material which tends to fall 13 in a direct downward path within the shell grooves 23 is arrested by the inclined surfaces 25 of the ledges 24 and deflected into engagement with the rotating plug. As the material travels downwardly through the annular passage 42 towards 1 5 the lower end of the shell it is of course gradually reduced in mass but this is compensated for by the gradual increase in the surface velocity of the lower portions of the frusto-conical plug with which the reduced particles of material 1 0 are gradually brought into contact during their downward progress.

Since the conical plug is mounted to turn at high speed about a fixed vertical axis in concentric relation to the surrounding shell it is 145 evident that this plug gives a certain fly wheel effect for storing up energy so that any material which is caught between the lower portions of the plug and shell is crushed by attrition without seriously impeding the high speed of operation. 150

The decrease in the pitch or fineness of the grooves-23 and 29 as they approach the lower ends of the shell and plug compensates to some extent for the gradual reduction in the mass of the particles travelling downwardly in the annular passage 42. I

The particular operating speed of the rotor or conical plug will vary according to the particular design of the machine but must, in all cases, be suificiently high to produce, in the material being treated, the velocities necessary to cause the material to be hurled into crushing impact with the shell during its downward travel through the passage 42. g

A further advantage of the present invention is that when materialsa e crushed in a wetstate to eliminate the objectio and losses incident to the production of floating dust during the be used'to' keep down the dustand to prevent p g.

Having thus described-our invention, what we claim is:--

1. A centrifugal crusher comprising a stationary upright shell, 9. vertical shaft" passing centrally through the shell and mounted to rotate in suitable bearings, .the portion of the shaft surrounded'bythe shell being stepped to present a vertical series of cylindrical sections of different diameters, .:each "section being of uniform diameter throughout its length and of a diameter slightly smaller than that of the next lower section, a closely fitting ring sur rounding each of said cylindrical sections, each ring being made of gradual decreasing diameter towards its lower end so that its outer surface forms a symmetrical continuation of the corresponding surface of the ring next above so that the several rings form a plug of frusto-conical construction, the outer surfaces of said rings being also corrugated to afford alternating ridges and valleys extending lengthwise of the plug.

2. A centrifugal crusher comprising a vertical shell formed with a slight inward taper towards its upper end, a base casting supporting the lower end of said shell, said base casting having a sloping bottom wall formed to provide a vertically disposed shaft bearing, a feed chamber mounted at the upper end of said shell, and

equipped with a shaft bearing in line with said.

first mentioned bearing, a vertical shaft passing centrally through said shell and having its upper and lower ends rotatably mounted in said bearings. a deflector positioned within the feed chamher and carried by the upper end of said shaft, a liner for the inner surface of said shell comprising a plurality of impact rings arranged one above the other and held in place between opposing surfaces of the base casting and the feed chamber, and a frusto-conical plug construction carried by the portion of the shaft passing through said shell, said plug construction aifording a substantially uninterrupted impact surface of a length substantially corresponding to that afforded by the inner sides of the opposing shell rings.

HUBERT G. lN'ElZ-SFORD. ANDREW N. :RUSSELL. 

